[rmlew]

Most American Jews are descended from those who came prior to 1923. (As a side note, Jews who came since 1945 tend to be Republican or independent.)

As for the rest of your theory, wealth could also be an impediment. Many wealthy Jews refused to leave their property, as they like so many others did not understand the genocidal intent of the Nazis until it was too late.
My mother's father tried to escape with his 4 brothers, which was made easier because they had so little property to leave behind. (1 brother died as then fled the Nazi advance through Poland in 1939, 2 died in Soviet gulags, 1 later died of cancer after mining for heavy metals in a Soviet gulag.) My maternal grandmother came from a wealthy family. She fled alone, although some of her poorer cousins separately fled to the USSR. As far as we know, everyone else died in Majdanek. My father's family used their wealth to try to help their neighbors escape, as well as protect themselves. They eventually fled.

[douginthearmy]

I am not trying to rub any salt in any wounds and you have a personal connection to the issue so I have no desire to offend you. I am just going by pure numbers and math which may seem cold, but the post was in reference to average IQ which in and of itself removes the issue from the individual level and speaks of whole groups. A large number of Ashkenzai Jews (who are those with the measured higher average IQ) descend from those Jews living in Poland who had the means to escape to the Soviet Union. It is quite possible that this may have accounted for at least some shift upwards in the average intelligence.